Justify buttons with Bootstrap v4

Question

Bootstrap v4 drops the .btn-group-justified class, see https://github.com/twbs/bootstrap/issues/17631

How to justify the button for:

Answer 1

Building on Bass Jobsen's great answer, here is the same functionality using flexbox instead of display: table;

SCSS code

// Justified button groups
// ----------------------

.btn-group-justified {
  display: flex;
  width: 100%;
  .btn,
  .btn-group {
    flex: 1;
    .btn {
      width: 100%;
    }
    .dropdown-menu {
      left: auto;
    }
  }
}

HTML

   Left
   Middle
   Right
 

Please refer to Bass Jobsen's answer for more details on usage with dropdowns, HTML Links and more.